1. Field of the Invention
The present invention relates to a processor, a clock determining method and a drive voltage determining method that are capable of reducing power consumption of a processor for data processing. Especially, the present invention relates to a processor having storage regions for storing data to be processed in the form of divisional execution units respectively.
2. Related Background Art
A processor intended for data processing normally needs a clock as the reference of the synchronization of processing by individual means of the processor.
The higher the frequency of the clock as the reference of synchronization of respective means of a processor, the higher the processing speed of the entire processor will be increased, and the processing rate per unit time will increase (enhancement of the throughput).
However, as the clock frequency becomes higher, signals flowing through internal wirings of the processor can not match the speed, and it will be necessary to raise the voltage supplied to the processor. Such a limit in the flow rate of signals relative to a certain voltage is caused by the floating capacitance and the electric resistance inside the processor. Because the structures of processors are composed of semiconductors, it is difficult to remove all these disadvantages.
Any increase in the drive voltage of a processor invites an increase in the electric power consumed in the processor. This invites not only an increase in the power consumption but also an increase in heat generated therein, which may adversely affect the integration of processors.
For these reasons, it is important to limit the clock frequency of the processor in operation to limit the power consumption of the processor itself.
To limit the power consumption, some methods have been proposed. In one method, an operating system used to control a processor selects low-frequency clocks for execution of units of tasks with lower priorities (for example, Japanese Patent Laid-open Publication JP2001-202155A). In another method, the supply of clocks is interrupted when there is ample time for processing (for example, Japanese Patent Laid-open Publication JP2002-358139A).
In typical processors intended for data processing, the higher the driving clock frequency the higher the processing efficiency. However, it results in increasing the power consumption of the processor and hence increases the heat generated therein.